Internal combustion engine



Aug. 4, 1931.

Filed Jan. 3. 1927 2 Sheets-Sheet I 5 H 3 3 w w; I MN I U k f d Q a Q I2 22 0 M m E mm aywmtoz R V. L gnarl- Y 2 Sheets-Sheet 2 R. v. HARTLEY INTERNAL comansnou ENGINE Filed Jan. 5. 1927 II/IIIIIIIIIIIIIII -IIIIIIIIIIIlIIlIIIII// Aug. 4, 1931.

gvweutoz R, V. L. /A re TLEY @5 L14 alt 0614 IIIIIIIIIIIIIIIIII Patented Aug. 4, 1931 I RALPH L HARTLEY, OF SOUTHQRANGE, NEW JERSEY INTERNAL COMBUSTION ENGINE Application filed January 3, 1927. Serial lid-158,449:

the ratio of mean pressure or average pres-' sure to maximum pressure isgreater than heretofore. a

A further object ofthe resent invention resides in. the provision oi means whereby overall operating efliciencies of engines may be increased. This is effected by eficiently lowering the premure peak in the engine so that lighter moving parts may be utilized than heretofore.

Another object of the present invention resides in the provision ofan engine construction in which high power output may be .tem orarily secured in a simple manner. uch temporary high output is secured at the sacrifice of. efliciency, but-this "is not objectionable when such greatly increased output is only derived for short periods as for-starting a given load or the like. A further object resides in the provision of an engine construction which is capable of relatively greater output at low speeds to the end that less changing of gears is necessary under varying conditions of operation. 3 I Y Other and-incidental objects residevin the provision of improved scavenging means for engines, thedilution of the char e independently of 5 the compression ratio 0 the engine.

thus making it'possible to control I Another object of the present invention, resides in the provision of an engine of "such character'that it is adapted for use with a variety of fuels and particularly such fuels ,as would heretofore cause excessive pressures which would cause damage to. 7 previous engines. I

The engine also has utility in connection with modern 'pression ratios without attendant fuel de 55 tonation. My engine-is'adapted to utilize such fuels and increasethejoperating'efliciency over present engines by affording a greater expansion ratio and also "by permittmg a greater compression ratio to be 6 employed for an engine of given strength and structural design.

Another. object resides in the. provision of an engine construction in whichthe tendency to fuel detonation is reduced by pro- 6 viding that under those conditions of operation where it would otherwise be most likely tooccur, combustion-takes place at substantially constant pressure rather than at constant volume as in the present engines- -A further object resides in the provision of an engine construction in which the production of vibration in the engine and associated structures. reduced by restricte ing the sudden-increase in pressure ,in the 75 combustion chamber which normally ac-. companies the explosion of the" charge/j Further and other objects and advantages will be hereinafter-set forthin-more detail in .the accompanying specification and 30 claims and shown in the; drawings. whieh by way of illustratioinshow what-I now consider to bee preferred embodiment of the invention.

In the drawings: v Figure 1 is a vertical sectional view of my improved engine;

Figs. '2' to 5 inclusive,' are detail views which show therelation in various steps of the cycle of operation. a

fuels which aiford higher com- Referring to the drawings in more detail, the engine has the conventional crank 10, connecting rod 11' and wrist pin 12 and valve gear comprisingcamshaft 13 which operates the usual inlet and exhaust valves 14 and 15 which are. of conventional form -(see Fig. 5). Any Suitable well known ignition means such as spark plug 16 may be used.- r v According to the present invention, provision is made for first utilizing a relatively greater crank throw. This per se ofcourse, would increase the expansion ratio for a givenv clearance volume. Provision is then made for securin an expansion ratio which not only difi'ers rom the compression ratio but which is greater than the compression ratio whereby higher efficiencies. and the other advantage heretofore mentioned are secured. p

The manner of securing these results will -now be described.

Iffirst provide a compound piston structure comprising an inner or main piston 20 operatively connected to the wrist pin with an outer or supplementary piston 21 telescoping the inner piston. The'outer piston is provided with a lug 22 secured in any manner as by threading thereto, which slidably fitsthe lower and reduced portion of the inner piston and affords an annular air pockets ace 23 therebetween. This pocket 1s provi ed with ports 24 which open into the interior of the inner piston or crank 3 chamber. As will later be explained, relative vertical motion occurs between the in.- n'er and outer piston and upon the suction stroke (see Fi 2), the ports 24 ,aresealed olf and thus a ord an air cushion to prevent I Q the ring 22 from striking the flange portion of the inner piston. The outer piston is provided with a series of ports 25 around the periphery with intervening connecting s web portions. Disposed in the inner piston are. a plurality of other ports 26 which upon all strokes connect the'ports 25 with theinterior of the inner piston and correspondingly to the crank case. As shown in Fig.- 2 u on the suction stroke, theaforesaid series 0 ports 25 and 26afiord a free open:

ing to the pocket space 27 intermediate the head of the outer and. inner pistons. This opening just mentioned issealed ofl. during all other strokes. Y

The action of the compound piston. during' the various strokes will now .be described. I Upon the suction stroke the inner piston is mechanically drawn down by the connecting rod. The pressure above the ,outer'piston being relatively. low,the outer piston lags relativeIy to the downwardmov'ement p "of the-inner piston and finally"as'sumes the I position shown in Fig. 2 at ,the' end of the Y li suction stroke. As-anincideutaladvantage the inertia of the outer piston upon the downward movement tends to continue its downward movement at the time the inner of the inner piston. It will be understood,- that the compression pressure of the charge in combustion space 28 will at all times equaliae with the pressure in space 27. Fig. 3 shows the relative position of the parts at the end of the compression stroke. Y

Ignition now takes place and the expansion stroke follows (see Fig. 4). Obviously the pressure above the upper greater than the pressure in space 2 and the outer piston is forced down against the reaction of the air or gas in space 27. This space decreases on account of the higher pressure above the outer piston until the pressure above and below. the outer piston stroke proceeds the upper and outer pistons relatively recede from each other as the explosion pressure falls. The pressure at the end of the expansion stroke is greater than atmospheric pressure and obviously the outer piston does not mode. out relatively to the inner piston to an extent comparable with the position assumed upon a suction stroke in which case the pressure above the iston is is balanced (see Fig. 4). As the expansion outer piston is less than atmospheric pres- 4 sure.

When the exhaust valve opens the-pressure above the upper piston falls. The pres- .sure still exists below the upper piston and accordingly this piston moves out andscavenges the-combustion space of the exhaust gases. I

position at the of the suction, stroke until its lowering movement isagain initiated by the action of air cushioning in pocket 23. If desired the scavenging action Moan be dispensed by dispensing" with the entrappedjgas space above the inner pig ton. In thiscase the inner piston wolild directIy'siI port-the outer piston but an .air CllShiOHWOflld be provided'between the two ,pistons.v I also The upper piston. remains in this provide'a relatively movable c linder head for th'e combustion space. T 's improvement may' 'be. dispensed with "or i 'Iutiliz'ed as desired connection with the piston actlon previously described, but in utility both in explosive engines and Diesel typeengines. The piston devices previously described are not particularly suitable for two cycle engines of the explosive or Diesel type and in such cases the movable head devices can be utilized. Both the movable head and the piston arrangements can be used in combination in four cycle explosive or Diesel engines. The movable head can also be used in two cycle explosive or Diesel engines and the piston device itself can also be used in four cycle explosive or.

Diesel engines. I

Abovethe combustion chamber, I provide a piston typehead, generally designated at and preferably but not necessarily of differential piston form including. a smaller piston 31 and larger piston 32, 31 is directly acted upon by the pressure in the combustion space 28. 4 a chamber or space 33. which may be termed a pressure storage chamber which is preferably larger in volume as compared to the combustion chamber. The differential piston is preferably hollow so as to permit oil to be admitted through Gases of combustion are introducedinto pressed valve or other equivalent :device. The gases pass from this valve to a passage Above the larger piston 32 isport 34 to both cool the piston and effect lubrication thereof.-

charge-the pressure in chamber 33 becomes 7 sufiicient to close valve 37, after which it remains substantially constant. I Under the first condition the pressure in the passage 36 \then builds up to a value greater than that in 33 in approximately the ratio of the areas of the piston surfaces 32 and 31, after which valve 35 remains closed. On each succeeding explosion the pressure in the combustion chamber 28 rises .to the value of that in passage 36. As it tends to rise further, the piston 30 moves upward under the action of the unbalanced forces so as to tend to maintain the pressure in 28 substantially constant. (See Fig. '4). As the combustion stopsv and the expansion stroke gets under way the pressure in 28 which would other- W186 fall .is maintained constant by the downward motion of piston 30 under the action of the pressure in chamber 33. This lower ng action continues until the difli'erent1al plston seats upon seat 42-or until it is arrested by the gas cushion above the seat.

Thereafter expansion inthe engine cylinder occurs in the ordinary way.

In the .second condition the developed combustion pressure-is more than enough to cause valve 37 to close but is below that which would cause mover'nentof piston 30.

when 37 is closed. Under this second condition the pressure in chamber 33 builds up until valve 37 closes after which it remains constant as bef re The pressure in passage 36 builds up to the developed combustion pressure after which the valve 35 remains closed and thepressure remains' constant.

(The'spring upon valve 35 is intended to,

exert no appreciable loading-of the valve.

36 leading to the chamber 33 which. passage ltmerel serves-to seat the valve and is not is provided with any suitable control means as for instance,slide valve 37. Inorder to control the action of valve 37 1 preferably may be made adjustable in any suitable manner as'by adjoined device 45.

The action of the head is as follows:

Before supplying-fuel to the engine a pressure equal to or above the compression pressure must be built in-chamber 33. This can be done by usingthe engine as a pump with the fuel supply cut oil'- or any suitable means such as a hand pump can be used. This is necessary to prevent. an accumulation of explosive mixture in chamber 33.

Then upon operating the engineupon the explosion cycle the valve 35- opens and burnt mixture passes into chamber 33. Gas con "tinues to accumulate in 33 until one of three 3 conditions of. equilibrium is reached. In

the first which'corresponds to a. heavy lntende to bring about a material loading thereof) Thepiston 30 then remains at rest throughout: the explosion stroke. In the third conditioni'the developed combustion pressure is less than thepressure at which valve 37 closes. The operation then differs from thatin the second condition only in that valve 37 remains open and'the pressure in chamber 33 as well as i'n'passage 36 remains equal to the developed combustion pressure.

It is obviousthat in all except the'first condition the .operation i'sno different from that of the ordinary engine.

When the charge is changed as by altering the positionof the throttle a new equilibrium is automatically established. If the.

charge is increased the mode ofoperation is identlcal with that already described. If it is decreased the pressures in chamber 33 and passage 36 remain at their original values but it will "be readily seen that the desired operation with the new charge will not be altered thereby.

The above action allows the engine toop- I crate at low loads with full efiiciency and yet permits high peak pressures to be eliminated tends to fall off while the period of com bustion becomes longer relative to the period of the expansion stroke. Both of these factors tend to limit the combustion pressure. Hence it is relatively less important that the pistonfunctions perfectly at high speeds. At low speeds there is time for a full charge to be drawn in and the combustion takes place before the expansionstroke has prospondinglgeincreased.

It will understood that when the pressure peak is cut off, it is particularly desirablec to have as great an expansion who as possible since the cutting'ofi of the pressure peak brings about in the present embodiment an increased pressure at the end of the expansion stroke. It is accordingly desirable to utilize this pressure which can be readily done withv the piston structure herein described.

It will be understood that the storage chamber 33 can, if desired, be common to all the cylinders of the engine. One or a multiplicity of valves 35-37 may be provided as desired.

What Iclaim is:

1. In an internal combustion engine in combination with a cylinder, apiston structure therein havin a single operating connection to a. cra means comprising air pockets which are sealed'ofi and opened by the action of the piston structure associated with the said piston structure for automati- .cally changing the. volume ratio swept by said piston from one ratio to another upon compression and expansion strokes.

2. In an internal combustion engine, a

, cylinder, a main piston operatively connect ed to the crank, and a supplementary pisi ton cooperatively associated with the main iston, andmeanscomprising air cushions tween'the istons and controllin ports in the pistons or automatically relatlvely displacmg' said pistons with respect to each 5 other to aflord one compression ratio and a 'difi'erent and greater expansion ratio upon the c clic operation of the engine.

3. 'lhev invention set forth in claim 2 in which air cushion means are provided inter-' mediate the heads of the ,pistons for cushioning their relative action with respect to each other and in which means is provided for relieving the air pressure induced in said air cushioning means cyclicly upon each stroke.

4. An internal combustion engine includ-- ing a compoundpiston structure with a main and supplementary piston, and means including porting valve means which are controlled for valving action by the main and supplementary pistons for utilizing the gas pressures upon said compound piston structure to secure variable volume' ratios upon the compression and expansionstrokes for the purpose described. I 3 5. An internal combustion engine with a combustion chamber, a pressure storage chamber and a piston'device therebetween, means to conduct gases from the combustion chamber to said storage chamber, and valve means controlled by the pressure in the storage chamber and irrespective of the pressure in the combustion chamber to cut oil the flow of gases thereto upon determined lionditions of pressure in the storage cham- 6. An internal combustion engine with a combustion chamber, a pressure storage chamber and a piston device therebetween,- means to conduct gases. from the combustion chamber to the storage chamber, and a dual valve means intermediate the combustion chamber and the storage chamber, one valve means having provisions to cut off the back flow of gases to the combus- 9 tion chamber and the other valve means having PI'OVISiOII S to cut oil the flow of.gases to or from the' ipressure chamber, said last mentioned valve means being controlled to be maintained in closed condition irrespec f" two of the relative pressure difierences-in the combustionchamber and pressure stor lf agechamber. v v 7. An internal combustion enginehaving a combustion chamber and a-pressure storage chamber and a diflerential pistontherebe-- tween, and means for admittin a cooling medium to the interior of said piston device for cooling the latter, said means having provisions for keeping-the cooling medium separate'from the gases which act upon the differential piston and which come from the pressure storage chamber. I

8. An internal combustion engine having acombustion chamber and a pressure stor 1 5 age chamber and a hollow differential pis- L.

ton therebetween, and means for admitting lubricant to the hollow portions of said piston during back and forth movements thereof. I

combustion space,

signature.

9. An internal combustion engine having a plurality of engine cylinders each with a a pressure storage chamber common to a plurality of said cylinders, and piston devices between said pressure storage chamber and the combustion space of each cylinder, each piston device being at all times during the cycle 'of the operation of the engine subject to the pressure in the common pressure storage chamber.

In testimony whereof I hereto afiix my RALPH v. L. HALRTLEY. 

